Audio jacks with optical and electrical paths

ABSTRACT

Electronic devices are provided that communicate over cables and other communications paths that include optical and electrical paths. A cable may include wires for forming an electrical path and one or more optical fibers for forming an optical path. Connectors at one or both ends of the cable may include electrical contacts and an optical coupling structure associated with the optical path. Optical paths may be included in connectors such as tip-ring-sleeve connectors and connectors of other types. Interface circuitry may be included in a connector to convert between optical and electrical signaling schemes. Wavelength-division-multiplexing may be used to support bidirectional communications. Breakout boxes and other equipment may be connected using the cables. Digital signals such as digital noise cancellation signals may be conveyed over the optical paths. Power and other electrical signals may be conveyed over the electrical paths.

BACKGROUND

Electronic devices such as computers, media players, and cellulartelephones typically contain audio jacks. Accessories such as headsetshave mating plugs. A user who desires to use a headset with anelectronic device may connect the headset to the electronic device byinserting the headset plug into the mating audio jack on the electronicdevice. Miniature size (3.5 mm) phone jacks and plugs are commonly usedelectronic devices such as notebook computers and media players, becauseaudio connectors such as these are relatively compact. Because 3.5 mmphone jacks and plugs are sometimes used to carry video signals, 3.5 mmaudio connectors such as these are sometimes referred to as audio-video(A/V) connectors.

Headsets and other accessories have speakers that can be used to playback audio for a user. Some accessories have microphones. Microphonescan be used to pick up the sound of a user's voice. This allows anelectronic device to be used to record voice memos. Electronic deviceswith cellular telephone circuitry can use a microphone on an accessoryto gather the user's voice during a telephone call.

In some headsets, microphones are used to form part of a noisecancellation circuit. When noise cancellation functions are active, theimpact of ambient noise on audio playback can be reduced. Microphonescan also be used to implement voice microphone noise cancellation.

Noise cancellation operations are generally implemented using analognoise cancellation circuitry. The analog noise cancellation circuitrysubtracts a weighted version of the microphone signal from the audiosignal.

Although conventional noise cancellation circuit arrangements can besatisfactory in some situations, recent advances in headphone qualityand audio playback fidelity are placing increasing burdens onconventional noise cancellation circuits. These burdens are making itdifficult or impossible to implement desired levels of noisecancellation performance with conventional approaches.

Conventional audio-video connector arrangements may also make itdifficult or impossible to implement desired functionality in a system.For example, conventional 3.5 mm jacks and plugs and associated cablesmay not exhibit sufficient bandwidth for conveying large amounts ofdata.

SUMMARY

Electronic devices and external equipment such as headsets and otheraccessories may handle digital signals. These digital signals mayinclude digital audio and digital video data. Audio-video (A/V)connectors, which are sometimes referred to as tip-ring-ring-sleeve(TRRS) connectors, tip-ring-sleeve (TRS) connectors, or audioconnectors, may include electrical and optical components. For example,an audio connector may include electrical contacts that are coupled toelectrical transceiver circuitry and an optical path that is coupled tooptical transceiver circuitry.

An electronic device may be provided with audio digital signalprocessing circuitry. Switching circuitry may be configured to ensurethat appropriate sets of electrical signal paths are formed. Forexample, in configurations in which no optical functions are needed, theswitching circuitry can be configured to couple electrical datatransceiver circuitry or analog circuitry to the electrical contacts inan audio connector. When optical functionality is desired, the switchingcircuitry can be configured to route power signals over the electricalpaths while optical signals are being used to convey potentially largeamounts of digital data.

Audio connectors can include conductive contact structures (e.g., tip,ring, and sleeve conductors). These conductors may be separated byinsulating structures. For example, a ring of insulator may be locatedbetween each of the conductors. Optical functionality can beincorporated into the audio connectors using coaxial optical paths or,when transparent material is used for the insulator that is locatedbetween respective conductive contacts in the audio connectors, byconveying light radially through the insulator.

Audio connectors with optical and electrical capabilities may be used inelectrical devices and cables and in external equipment such as breakoutboxes and other accessories. The optical capabilities of the connectorscan be used to convey video data, audio data such as noise cancellationdata, or other suitable data.

Further features of the invention, its nature and various advantageswill be more apparent from the accompanying drawings and the followingdetailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an illustrative electronic device incommunication with an accessory such as a headset, breakout box, orother external equipment in a system in accordance with an embodiment ofthe present invention.

FIG. 2 is a diagram showing how a communications path that includes atip-ring-sleeve connector can be used to allow equipment to interact inaccordance with an embodiment of the present invention.

FIG. 3 is a schematic diagram showing illustrative circuitry that may beused in an electronic device to electrically and optically communicatewith an accessory and to provide processing and power supply functionsin accordance with an embodiment of the present invention.

FIG. 4 is a circuit diagram of illustrative circuitry in an accessorythat performs processing functions and that electrically and opticallycommunicates with circuitry in an electronic device such as thecircuitry of FIG. 3 in accordance with an embodiment of the presentinvention.

FIG. 5 is a diagram of an illustrative system in which electronicequipment such as a breakout box serves as an interface between anelectronic device and other equipment in accordance with an embodimentof the present invention.

FIG. 6 is a diagram showing how an electronic device may communicatewith external equipment using a cable having connectors with optical andelectrical components in accordance with an embodiment of the presentinvention.

FIG. 7 is a diagram showing how an electronic device may communicatewith external equipment using a cable with a connector at one end thathas optical and electrical components in accordance with an embodimentof the present invention.

FIG. 8 is a circuit diagram showing how an electronic device maycommunicate with external equipment using a cable that containsoptical-to-electrical and electrical-to-optical interface circuitry inaccordance with an embodiment of the present invention.

FIG. 9 is a cross-sectional diagram of an illustrative cable containingfour wires and an optical fiber in accordance with an embodiment of thepresent invention.

FIG. 10 is a cross-sectional diagram of an illustrative cable containingfour wires and two optical fibers in accordance with an embodiment ofthe present invention.

FIG. 11 is a cross-sectional diagram of an illustrative jack and plugthat are coupled to a cable having an optical fiber and wires inaccordance with an embodiment of the present invention.

FIG. 12 is a diagram of an optical path coupled to a pair of opticaltransceivers in accordance with an embodiment of the present invention.

FIG. 13 is a perspective view of an illustrative pair of audioconnectors that have mating engagement features in accordance with anembodiment of the present invention.

FIG. 14 is a cross-sectional diagram of an illustrative plug and matingjack of the type shown in FIG. 13 showing how an optical source andoptical detector may be coupled to respective optical fibers in a cablein accordance with an embodiment of the present invention.

FIG. 15 is a perspective view of an illustrative plug having annulartransparent portions through which light may be conveyed to opticalfiber structures in an attached cable in accordance with an embodimentof the present invention.

FIG. 16 is a perspective view of a portion of an electronic devicecontaining a jack and associated annular source and detector regionsthat may mate with the annular transparent jack regions in a jack of thetype shown in FIG. 15 in accordance with an embodiment of the presentinvention.

FIG. 17 is a cross-sectional side view of a system based on a plug ofthe type shown in FIG. 15 and jack of the type shown in FIG. 16 inaccordance with an embodiment of the present invention.

FIG. 18 is a cross-sectional side view of an illustrative plug-and-jacksystem in which the plug has transparent ring-shaped insulators and thejack has matching source and detectors in accordance with an embodimentof the present invention.

FIG. 19 is a perspective view of an illustrative electronic device andan associated accessory that has a vertically mounted protruding hybridplug that is received by a hybrid jack in the electronic device inaccordance with an embodiment of the present invention.

FIG. 20 is a flow chart of illustrative steps involved in configuringand using electrical equipment that has optical and electricalconnectors in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION

Electronic components such as electronic devices and other equipment maybe interconnected using wired and wireless paths. For example, awireless path may be used to connect a cellular telephone with awireless base station. Wired paths may be used to connect electronicdevices to equipment such as computer peripherals and audio accessories.As an example, a user may use a wired path to connect a portable musicplayer to a headset.

In a typical wired path, wires are used to handle electrical signals.One or more optical fibers may be included in the same wired path as thewires. For example, a cable may contain four wires and one or twooptical fibers (as an example).

With an arrangement of this type, the optical fiber or fibers in thecable may form an optical path and the wires may form an electrical paththat runs in parallel with the optical path. The optical and electricalpaths may be used to convey digital data such as audio data, video data,control signal data, etc. If desired, power signals and analog signalscan be conveyed over the electrical path.

Connectors may be provided in a wired path that contains electrical andoptical paths. For example, male and/or female connectors may beprovided at one or both ends of a cable or may be used in directlyconnecting an accessory to an electronic device.

Electronic devices that may be connected to external equipment usingoptical and electrical paths include desktop computers and portableelectronic devices. The portable electronic devices that are connectedto the external equipment in this way may include tablet computers,laptop computers, and small portable computers of the type that aresometimes referred to as ultraportables. The portable electronic devicesmay also include somewhat smaller portable electronic devices such aswrist-watch devices, pendant devices, and other wearable and miniaturedevices.

The electronic devices that are connected to external equipment may alsobe handheld electronic devices such as cellular telephones, mediaplayers with wireless communications capabilities, handheld computers(also sometimes called personal digital assistants), remote controllers,global positioning system (GPS) devices, and handheld gaming devices.The electronic devices may be devices that combine the functionality ofmultiple conventional devices. For example, the electronic devices maybe cellular telephones that have media player functionality, gamingdevices that have wireless communications capabilities, cellulartelephones that include game and email functions, and portable devicesthat receive email, support mobile telephone calls, have music playerfunctionality, and support web browsing. These are merely illustrativeexamples.

An example of external equipment that may be connected to such anelectronic device using optical and electrical paths is an accessorysuch as a headset. A headset typically includes a pair of speakers thata user can use to play audio from the electronic device. The accessorymay have a user control interface such as one or more buttons. When auser supplies input, the input may be conveyed to the electronic device.As an example, when the user presses a button on the accessory, acorresponding signal may be provided to the electronic device to directthe electronic device to take an appropriate action. Because the buttonis located on the headset rather than on the electronic device, a usermay place the electronic device at a remote location such as on a tableor in a pocket, while controlling the device using conveniently locatedheadset buttons.

The external equipment that is connected to the electronic device mayinclude equipment such as a tape adapter. A tape adapter may have a plugon one end and a cassette at the other end that slides into a tape decksuch as an automobile tape deck. Equipment such as a tape adapter may beused to play music or other audio over the speakers associated with thetape deck. Audio equipment such as the stereo system in a user's home orautomobile may also be connected to an electronic device using opticaland electrical paths. As an example, a user may connect a music playerto an automobile sound system using a three-pin or four-pin audioconnector that includes an optical path.

In some situations, it may be desirable to convey relatively largeamounts of data between the electronic device and accessory. Forexample, if the accessory has video playback capabilities (or is coupledto equipment that has video display capabilities), the optical andelectrical paths between the electronic device and the accessory may beused to convey relatively large amounts of data (e.g., video data andaccompanying soundtrack information, image data, etc.). The data that isconveyed between the electronic device and the accessory may be carriedover the optical path and/or the electrical path as digital data.

As another example, the data that is conveyed between the electronicdevice and the accessory may include audio data. For example, digitalaudio data from a microphone or digital audio data that is being playedback from storage may be conveyed over the optical and/or electricalpaths. When an optical path between the electronic device and accessoryis available, it may be possible to convey larger amounts of databetween the electronic device and accessory than would otherwise bepossible. For example, an optical path may be used to convey data atdata rates of tens of Mbps or more, hundreds of Mbps or more, or a Gbpsor more. Optical paths may also be suitable for incorporation intominiature parts such as 3.5 mm TRS connectors.

In a typical scenario that involves the transmission of audio data, theelectronic device that is connected to the external equipment producesaudio signals. These audio signals may be transmitted to the externalequipment in the form of analog and digital audio. For example, theelectrical path may include wires that convey analog audio to speakersin the accessory. The electrical and optical paths may be used to conveydigital audio data (e.g., pulse-code-modulation encoded digital audiodata).

The external equipment may include a voice microphone. One or more noisecancelling microphones may also be provided. Microphone signals (e.g.,analog audio signals corresponding to a user's voice, ambient noise, orother sounds) may be processed locally in the accessory. Microphonesignals may also be conveyed to the electronic device using theelectrical and/or optical paths.

The communications path between the electronic device and accessory maybe used to convey signals such as control signals in addition to audioand video signals. Digital data may be conveyed if desired. In general,data conveyed between the electronic device and accessory may includefor example, control signals, audio, video, information to be displayedfor a user, etc.

Accessories such as headsets are typically connected to electronicdevices using plugs (male connectors) and mating jacks (femaleconnectors). Connectors such as these may be provided in a variety ofform factors. Most commonly, these connectors take the form of 3.5 mm(⅛″) miniature plugs and jacks. Because audio signals and sometimesvideo signals are conveyed over 3.5 mm plugs and jacks, 3.5 mm plugs andjacks are sometimes referred to as audio connectors or audio-video (A/V)connectors. The 3.5 mm size is popular for earbuds and other headsets.Other sizes are also sometimes used such as 2.5 mm subminiatureconnectors and ¼ inch connectors.

In the context of accessories such as headsets, these audio connectorsand their associated cables can be used to carry analog signals such asaudio signals for speakers and microphone signals. Digital data streamsmay also be used to convey audio signals (e.g., audio output signalssuch as played-back media or telephone call audio, microphone signals,and noise cancellation audio), control signals (e.g., input-outputsignals), clock information, and other signals. Video may be conveyedwith or without audio (e.g., as digital data).

Analog signals such as analog audio signals may be conveyed overelectrical paths. Power may also be conveyed using electrical paths.Digital data may be conveyed using electrical and/or optical paths.Optical structures such as optical fibers and transparent windows may beincorporated into a communications path between an electronic device andexternal equipment. These optical structures may be incorporated intoaudio connectors (e.g., 3.5 mm jacks and plugs) or other connectors(e.g., digital data connectors such Universal Serial Bus connectors,30-pin connectors, XLR connectors, etc.). For clarity, the use ofoptical structures in audio connectors such as 3.5 mm jacks and plugs issometimes described herein as an example.

The audio connectors (audio-video connectors) that are used inconnecting an electrical device to external equipment may have anysuitable number of electrical terminals. The electrical terminals in aconnector are formed from conductive materials such as metal and aretypically referred to as contacts. Stereo audio connectors typicallyhave three electrical contacts. The outermost end of an audio plug istypically referred to as the tip. The innermost portion of the plug istypically referred to as the sleeve. A ring contact lies between the tipand the sleeve. When using this terminology, stereo audio connectorssuch as these are sometimes referred to as tip-ring-sleeve (TRS)connectors. The sleeve can serve as ground. The tip contact can be usedin conjunction with the sleeve to handle a left audio channel and thering contact can be used in conjunction with the sleeve to handle theright channel of audio (as an example). In four-contact audioconnectors, an additional ring contact is provided to form a connectorof the type that is sometimes referred to as a tip-ring-ring-sleeve(TRRS) connector or simply as a type of TRS connector. Four-contactaudio connectors may be used to handle a microphone signal, left andright audio channels, and ground (as an example). If desired, switchingcircuitry can be used to route different signals to and from thecontacts in a connector as needed to implement desired functions. Anoptical path may be incorporated into an audio connector such as a TRSconnector using one or more optical fibers and associated opticalstructures.

Electrical devices and external equipment may be connected in variousways. For example, a user may connect either a pair of stereo headphonesor a headset that contains stereo headphones and a microphone to acellular telephone audio jack. Accessories such as these may include oneor more noise cancelling microphones. For example, the voice microphonemay have an associated noise cancellation microphone that picks upambient noise in the vicinity of the voice microphone. The earbuds orother speakers in an accessory may also have noise cancellationmicrophones. For example, each earbud in a headset may have an externalnoise cancellation microphone on an outer surface of the earbud. Inaddition to the external noise cancellation microphone or instead of theexternal noise cancellation microphone, each earbud may have an internalnoise cancellation microphone on an interior surface of the earbud(adjacent to the ear).

In accessories with more speakers, more noise cancellation microphonesmay be used. For example, additional noise cancellation microphones canbe provided in earbuds that contain multiple drivers or in surroundsound accessories. A surround sound accessory might, for example, havefive or six speakers (or more) and might have a noise cancellationmicrophone that is adjacent to each respective speaker.

Electrical devices and external equipment may be operated in variousmodes. For example, a cellular telephone may be used in a music playermode to play back stereo audio to a user. When operated in telephonemode, the same cellular telephone may be used to play telephone callleft and right audio signals to the user while simultaneously processingtelephone call microphone signals from the user. Noise cancellationfeatures may be selectively turned on and off as needed. For example,microphone noise cancellation may be activated while earbud noisecancellation features are deactivated (as an example). Noisecancellation functions can also be globally deactivated or globallyactivated.

Electronic devices and external equipment may be provided with switchingcircuitry or other path configuration circuitry that allows theelectronic devices and external equipment to be operated in a variety ofdifferent operating modes in a variety of different combinations. When,for example, a user connects one type of accessory to an electronicdevice, the switching circuitry may be adjusted to form a first set ofelectrical paths between the electronic device and accessory. When auser connects a different type of accessory, the path configurationcircuitry may be adjusted to form a second set of electrical pathsbetween the electronic device and accessory.

Consider, as an example, the use of an electronic device that has afour-contact TRS jack with integrated optical structures for supportingoptical path communications. When a user of device plugs a conventionalstereo headset into the electronic device, switching circuitry in theelectronic device can be configured to route left and right analog audiooutput signals to speakers in the headset through the electricalcontacts of the TRS jack. When the user plugs a headset that includesnoise cancellation microphones into the device, the switching circuitrycan be configured to route power to the headset while the optical pathis used to convey digital noise cancellation signals between the headsetand the device. Another possible scenario involves the use of videoequipment. A user may, for example, plug video equipment into the TRSjack. In this situation, the electrical contacts in the jack may be usedto convey control signals or power while the optical path is used toconvey audio and video data.

Noise cancellation functions may be implemented in the externalequipment or in an electronic device. In schemes in which digital audiosignals are conveyed from the accessory to the electronic device, thecircuit resources of the electronic device may be used to help implementdesired functions. This may help reduce the amount of circuitry that isincluded in a given accessory and may help minimize accessory powerconsumption. Digital audio processing may also be performed usingdigital processing circuitry that is primarily or exclusivelyimplemented within an accessory.

In configurations in which at least some of the communications betweenthe electronic device and accessory are implemented using digitalcommunications (optical and/or electrical), the capacity of theelectronic device and accessory to communicate can be enhanced. Forexample, digital communications may allow numerous channels of audio tobe conveyed between the electronic device and accessory in real time.Control signals and other signals may also be conveyed digitally. At thesame time, the electronic device may, if desired, include analogcircuitry that produces analog audio signals. When an accessory withdigital communications capabilities is connected to the electronicdevice, the electronic device and accessory can communicate digitally.When an accessory without digital communications capabilities isconnected to the electronic device, analog circuitry in the electronicdevice may supply analog audio signals to the accessory. For example, ifa stereo headset with two speakers and no microphone or controlcapabilities is connected to the electronic device, analog audiocircuitry may be used to supply left and right channels of analog audioto the speakers in the stereo headset. When a more advanced accessory isconnected to the electronic device, additional features may becomeavailable (e.g., digital audio processing for noise reduction, digitalcontrol capabilities, additional audio streams for surround soundspeakers, etc.).

An illustrative system in which an electronic device and externalequipment may communicate over a wired communications link that includesoptical and electrical paths is shown in FIG. 1. As shown in FIG. 1,system 10 may include an electronic device such as electronic device 12and external equipment 14. External equipment 14 may be equipment suchas an automobile with a sound system, consumer electronic equipment suchas a television or audio receiver with audio and/or video capabilities,a peer device (e.g., another electronic device such as device 12), abreakout box that serves as an interface between a multiple electronicdevices 12, or any other suitable electronic equipment. In a typicalscenario, which is sometimes described herein as an example, externalequipment 14 may be an accessory that contains speakers such as aheadset. External equipment 14 is therefore sometimes referred to as“accessory 14” or “headset 14.” Speakers in accessory 14 may be providedas earbuds or as part of a headset or may be provided as a set ofstand-alone powered or unpowered speakers (e.g., desktop speakers). Asshown in FIG. 1, equipment 14 may include I/O circuitry 32 and storageand processing circuitry 26.

A path such as path 16 may be used to connect electronic device 12 andaccessory 14. In a typical arrangement, path 16 includes one or moreaudio connectors such as 3.5 mm plugs and jacks or audio connectors ofother suitable sizes. Conductive lines in path 16 may be used to conveyelectrical signals over path 16. These lines may be, for example, copperwires covered with plastic insulation. An optical path in path 16 may beused to convey optical signals (i.e., light). The optical path may beformed using one or more optical fibers.

There may, in general, be any suitable number of conductive lines andoptical fibers in path 16. For example, there may be two, three, four,five, or more than five separate lines and one, two, or more than twooptical fibers. These lines and fibers may be part of one or morecables. Cables may include solid wire, stranded wire, shielding, singleground structures, multi-ground structures, twisted pair structures, orany other suitable electrical cabling structures. The cables may alsoinclude plastic fiber, glass fiber, multimode fiber, single mode fiber,and other suitable optical path structures.

Extension cord and adapter arrangements may be used as part of path 16if desired. In an adapter arrangement, some of the features of accessory14 such as user interface and communications functions may be providedin the form of an adapter accessory with which an auxiliary accessorysuch as a headset may be connected to device 12. Adapter functions mayalso be incorporated into a cable. This type of arrangement may be used,for example, in a cable that has both electrical and opticalcapabilities at one end, but that has only electrical capabilities atits other end.

Electronic device 12 may be a desktop or portable computer, a portableelectronic device such as a handheld electronic device that has wirelesscapabilities, equipment such as a television or audio receiver, or anyother suitable electronic equipment. Electronic device 12 may beprovided in the form of stand-alone equipment (e.g., a handheld devicethat is carried in the pocket of a user) or may be provided as anembedded system. Examples of systems in which device 12 may be embeddedinclude automobiles, boats, airplanes, homes, security systems, mediadistribution systems for commercial and home applications, displayequipment (e.g., computer monitors and televisions), etc.

Device 12 may include input-output circuitry 28 and storage andprocessing circuitry 30. Input-output circuitry 28 of device 12 andinput-output circuitry 32 of equipment 14 may include buttons,touch-sensitive components such as touch screens and touch pads,microphones, sensors, and other components for gathering input from auser. Input-output circuitry 32 and 28 may also include speakers, statusinductors such as light-emitting diodes, displays, and other componentsfor providing output to users. Circuitry 32 and 28 may also includedigital and analog communications circuitry for supporting electricaland optical communications over path 16 and for supporting wirelesscommunications. Storage and processing circuitry 26 and 30 may be basedon microprocessors, application-specific integrated circuits, audiochips (codecs), video integrated circuits, microcontrollers, digitalsignal processors, memory devices such as solid state storage, volatilememory, and hard disk drives, etc.

Device 12 may communicate with network equipment such as equipment 18over path 22. Path 22 may be, for example, a cellular telephone wirelesspath. Equipment 18 may be, for example, a cellular telephone network.Device 12 and network equipment 18 may communicate over path 22 when itis desired to connect device 12 to a cellular telephone network (e.g.,to handle voice telephone calls to transfer data over cellular telephonelinks, etc.).

Device 12 may also communicate with equipment such as computingequipment 20 over path 24. Path 24 may be a wired (electrical and/oroptical) or wireless path. Computing equipment 20 may be a computer, aset-top box, audio-visual equipment such as a receiver or television, adisc player or other media player, a game console, a network extenderbox, or any other suitable equipment.

In a typical scenario, device 12 may be, as an example, a handhelddevice that has media player and cellular telephone capabilities(sometimes referred to collectively as a cellular telephone). Accessory14 may be a headset with a microphone and a user input interface such asa button-based interface for gathering user input. Path 16 may be a fouror five conductor audio cable with an embedded optical path that isconnected to devices 12 and 14 using 3.5 mm audio jacks and plugs (as anexample). Computing equipment 20 may be a computer with which device 12communicates (e.g., to synchronize a list of contacts, media files,etc.).

Paths such as path 24 and 16 may be based on commonly available digitalconnectors such as USB or IEEE 1394 connectors, XLR connectors, audioconnectors, etc. These connectors may include electrical and opticalpaths. An advantage of using communications paths that are compatiblewith commonly-used audio connectors such as the 3.5 mm audio connectorsis that this type of arrangement may maintain compatibility with auser's existing collection of headsets and other legacy equipment.Arrangements in which the communications paths of system 10 areimplemented using audio connectors with a 3.5 mm form factor or otherarrangement that is compatible with conventional audio connectors aretherefore sometimes described herein as an example. This is merelyillustrative. In general, the communications paths and connectors thatare used in system 10 may include electrical and optical paths andcoupling structures of any suitable type.

In system 10, electronic device 12 and accessory 14 may includeswitching circuitry (also sometimes referred to as adjustable pathconfiguration circuitry) that can be used to selectively interconnectvarious circuits to the contacts in the audio connectors of path 16. Theswitching circuitry may be adjusted to support different modes ofoperation. These different modes of operation may result from differentcombinations of accessories and electronic devices, scenarios in whichdifferent device applications are active, etc. The switching circuitrymay be formed from one or more transistor-based switches. If desired,the switching circuitry may include hybrid circuits that can beselectively switched into use. When the hybrid circuits are not activelyused, the electrical communications path and associated connectorcontacts to which they are connected may be used for unidirectionalcommunications. When the hybrid circuits are switched into active use,the same electrical communications path and connector contacts may beused to support bidirectional signals (e.g., an outgoing left or rightaudio channel in one direction and an incoming microphone signal in theopposite direction). Bidirectionality may also be supported using timemultiplexing protocols.

Illustrative circuitry that may be associated with path 16 is shown inFIG. 2. Switching circuitry 160 may be provided in electronic device 12and switching circuitry 162 may be provided in accessory 14 or otherexternal equipment. Wired path 16 may be used to connect electronicdevice 12 and accessory 14. Path 16 may include audio connectors such asaudio connectors 34 and 38.

The audio connectors of path 16 may include an audio plug such as plug34 (i.e., a male audio connector). Plug 34 may have a prong-shapedmember that allows plug 34 to mate with a corresponding audio jack suchas audio jack (i.e., a female audio connector). Jack 38 may includeelectrical contacts that surround a cylindrical opening that receivesplug 34. These contacts may be formed from rings of metal, spring-loadedconductive structures, etc. Connectors 34 and 38 may be used at anysuitable location or locations within path 16. For example, audio jackssuch as jack 38 can be formed within the housing of device 12 and plugssuch as plug 34 can be formed on the end of a cable such as cable 70that is associated with a headset or other accessory 14. As shown inFIG. 2, cable 70 may be connected to audio plug 34 via strain-reliefplug structure 66. Structures such as structure 66 may be formed with anexternal insulator such as plastic (as an example).

Audio plug 34 is an example of a four-contact plug. A four-contact plughas four conductive regions that mate with four corresponding conductiveregions in a four-contact jack such as jack 38. As shown in FIG. 2,these regions may include a tip region such as region 48, ring regionssuch as rings 50 and 52, and a sleeve region such as region 54. Theseregions surround the cylindrical surface of plug 34 and are separated byinsulating regions 56. When plug 34 is inserted in mating jack 38, tipregion 48 may make electrical contact with jack tip contact 74, rings 50and 52 may mate with respective ring regions 76 and 78, and sleeve 54may make contact with sleeve terminal 80. Insulating regions 56 mayseparate the contacts in jack 38. In a typical configuration, there arefour wires 88 in cable 70, each of which is electrically connected to arespective contact in plug 34.

Cable 70 may also include optical path 200. Optical path 200 may beformed from one or more optical fibers. In the example of FIG. 2, path200 is formed from a single optical fiber. As shown in FIG. 2, path 200extends through the central core of plug 34 and mates with acorresponding optical path 206 in jack 38. Path 206 may be located inelectronic device 12 (FIG. 1) and may be used to convey optical signalsbetween optical transceiver 208 in device 12 and optical path 200. Inthis capacity, path 206 may be considered to form a part of path 200.

Transceiver 202 may be located in accessory 14. During opticalcommunications between device 12 and accessory 14, optical transceivers208 and 202 may communicate optically over path 200.

Switching circuitry 160 may receive analog signals via path 170. Forexample, switching circuitry 160 may receive analog audio output signalson path 170 and may switch these signals onto lines 168 when operatingin an analog output mode to support legacy analog accessories. Path 170may also be used to route power supply signals to appropriate contactsin jack 38. Switching circuitry 160 may handle digital electricalsignals using path 172. For example, when operating in a digital audiomode to support a digital-ready headset, switching circuitry 160 mayswitch digital audio streams that are received on path 172 onto lines168.

In electronic device 12, signals (e.g., digital signals) that areconveyed over path 200 optically can be handled using input-output path210. During data transmission operations from device 12, data fromprocessing circuitry within electronic device 12 may be provided to path210. Data that is received at path 210 may be converted into opticalsignals using transceiver 208 and may be routed to path 200 via path206. In accessory 14, optical signals from path 200 may be received bytransceiver 202. Transceiver 202 may convert received optical signals toelectrical signals that are provided on input-output path 204.Processing circuitry within the accessory may receive and process thesignals on path 204.

Accessory 14 can transmit optical data using transceiver 202. Processingcircuitry within accessory 14 can provide data to input-output path 204.Transceiver 202 may convert the electrical signals that are received atpath 204 to optical signals. The optical signals can be transmitted toelectronic device 12 using path 200. In device 12, optical signals frompath 200 may be conveyed to transceiver 208 via path 206. Transceiver208 may convert received optical signals to electrical signals that areprovided at path 210.

Transceivers 208 and 202 may include light sources and detectors. Forexample, each transceiver may include one or more light emitting diodes,one or more laser diodes, or other sources of light. These sources mayoperate at a single wavelength or wavelength division multiplexingarrangements can be supported using multiple wavelengths of light. Eachtransceiver may also include photodetectors such as p-i-n diodes, p-njunction diodes, photodiode arrays, etc.

Accessories may have fixed operating modes or adjustable operatingmodes. For example, a legacy analog headset may only operate in ananalog audio mode. As another example, a digital-capable headset mayoperate in both analog and digital modes. This type of multimodeoperation may allow a digital-capable headset to revert to an analogaudio mode when used with a legacy music player. To accommodate multipleoperating modes, accessory 14 may control the configuration of theswitches in switching circuitry 164. When operating in analog audiomode, analog signals that are being conveyed between device 12 andaccessory 14 can be routed through analog lines 174. When operating indigital audio mode, switching circuitry 164 can be configured to switchdigital path 176 into use and/or to use transceiver 202 to handledigital optical signals. These configurations need not be mutuallyexclusive. For example, switching circuitry 160 and 164 may, if desired,be placed into configurations in which a mixture of analog and digitalsignals are conveyed over path 16 while optical signals are beingconveyed over path 200. A typical mixture of signals over path 16 mightinclude power signals, optical and/or electrical control signals,optical and/or electrical audio signals, and optical and/or electricalvideo signals. Switching circuitry 164 may, if desired, be used toswitch an ultrasonic tone generation circuit into use (e.g., to sendelectrical ultrasonic tone codes from accessory 14 to device 12 thatcorrespond to button press events or other user input).

The signal assignments that are used in the audio connectors of path 16depend on the type of electronic device and accessory being used and theactive operating mode for the system. For example, when operating in alegacy analog mode, ring contact 52 may serve as ground (and maytherefore sometimes be referred to as the G contact of plug 34), tip 48may be associated with left channel audio (and may therefore sometimesbe referred to as the L contact of plug 34), ring 50 may be associatedwith right channel audio (and may therefore sometimes be referred to asthe R contact of plug 34), and sleeve 54 may be associated withmicrophone signals (and may therefore sometimes be referred to as the Mcontact of plug 34). The mating contacts of jack 38 may havecorresponding signal assignments.

As shown in FIG. 3, electronic device 12 may contain video, audio,communications, and control circuitry 180. Video circuitry in circuit180 may be used to generate video signals or to receive and processvideo signals. Audio circuit 182, which is sometimes referred to as acodec or audio codec, may be used to generate audio signals or toreceive and process audio signals. Audio circuit 182 may includeanalog-to-digital (A/D) converter circuitry 184 and digital-to-analog(D/A) converter circuitry 186. Analog-to-digital converter circuitry indevice 12 may be used to digitize analog signals such as analog audiosignals. For example, analog-to-digital converter circuitry 184 may beused to digitize one or more analog microphone signals. These microphonesignals may be received from accessory 14 over path 16 or may bereceived from microphone equipment in device 12. Digital-to-analogconverter circuitry 186 may be used to generate analog output signals.For example, digital-to-analog converter circuitry 186 may receivedigital signals corresponding to the audio portion of a media playbackevent, audio for a telephone call, noise cancellation signals, an alerttone or signal (e.g., a beep or ring), or any other digital information.Based on this digital information, digital-to-analog converter circuitry186 may produce corresponding analog signals (e.g., analog audio).

Audio digital signal processor 188 may be used to perform digital signalprocessing on digitized audio signals. For example, if operatingaccessory 14 in a voice microphone noise cancellation mode, digitalnoise cancellation signals from a voice microphone noise cancellationmicrophone in accessory 14 may be conveyed over path 16 to audio digitalsignal processor 188. Audio digital signal processor 188 may alsoreceive digital audio voice signals from the voice microphone inaccessory 14 and digital noise cancellation signals from speaker noisecancellation microphones. Using the processing capabilities of audiodigital signal processor 188, the digital noise cancellation microphonesignals from accessory 14 can be digitally removed from the digitalaudio voice signal and from digital speaker signals. Use of theprocessing power of device 12 in this way may help to reduce theprocessing burden that is placed on accessory 14. This may allowaccessory 14 to be constructed from less costly and less complexcircuitry. Power consumption efficiency and audio performance may alsobe enhanced. If desired, digital audio processing circuitry in accessory14 can be used to supplement or replace the audio processing functionsof audio digital signal processor 188. For example, digital noisecancellation circuitry in accessory 14 may be used in cancelling noisefor the speakers of accessory 14.

Electrical transceiver 190 may be used to support unidirectional orbidirectional electrical digital communications with a correspondingelectrical transceiver in accessory 14 over path 16. Optical transceiver210 may be used to support unidirectional or bidirectional opticaldigital communications with a corresponding optical transceiver inaccessory 14 over path 16. Optical transceiver 210 may have an opticaltransmitter 212 and an optical receiver 216. Transmitter 212 may includea light source such as light source 214. Light source 214 may be alight-emitting diode (LED), a laser diode, or any other suitable sourceof light. The light is produced by light source 214 may be visiblelight, infrared light, or may have other suitable wavelengths. Detector218 may be used by receiver 216 to convert incoming light signals fromoptical path 206 (which is an extension of path 200 of path 16) toelectrical signals. During optical data transmissions, light from source214 may be conveyed to optical path 200 of path 16 using optical path206.

Any suitable communications protocol may be used by transceivers 190 and210. For example, a protocol may be used that includes functions such aserror correction functions. Data may be sent in packets or othersuitable data structures. A clock that is produced by circuitry 180 ofFIG. 3 (e.g., by circuitry in transceiver 190) may be transmitted withthe data. For example, transceiver 190 and/or transceiver 210 may embeda variable clock in a transmitted digital data stream.

Power supply circuitry 220 may be used in providing power to theelectrical contacts in connector 38 (e.g., from a battery in device 12).

Switching circuitry such as switching circuitry 160 of FIG. 2 may beused to selectively connect the contacts of audio connector 38 to thecircuits of video, audio, communications, and control circuitry 180,power supply circuitry 220, and other circuitry in device 12. Forexample, when it is desired to supply analog audio output signals fromcodec 182 to connector 38, the switching circuitry can be adjustedaccordingly by the control and processing circuitry of device 12. Whenit is desired to route electrical digital signals to the audio contactsof audio connector 38, the switching circuitry can be used to connecttransceiver 190 to audio connector 38. Power signals and other signalscan also be selectively routed to connector 38 by switching circuitry160. Optical path 206 and associated optical path 200 of FIG. 2 may beused in conveying optical signals to and from device 12.

Illustrative circuitry that may be used to handle signal processingtasks for accessory 14 is shown in FIG. 4. As shown in FIG. 4, accessory14 may include components and processing circuitry 192. Circuitry 192may include components such as a battery, switches, a display, a touchscreen, a keyboard, integrated circuits, discrete components, etc.Circuitry 192 may also include components such as microphones andspeakers. In the example of FIG. 4, accessory 14 includes microphones222, 226, 230, and 231 and includes speakers 224 and 228 (shownseparately in the FIG.). Speakers 224 and 228 may be, for example, leftand right speakers in a pair of earbuds or left and right speakers inother external equipment. Microphones 222 and 226 may be noisecancellation microphones that are used to gather ambient noise signalsassociated with speakers 224 and 228, respectively. Using noisecancellation techniques, the ambient noise signals can be used to reducenoise in the audio being played through speakers 224 and 228. Noisecancellation techniques can also be implemented for microphones. Forexample, microphone 230 may be a voice microphone that is used to gatherthe user's voice during telephone calls or that is used to record audioclips. Microphone 231 may be used to gather ambient noise signalsassociated with the use of microphone 230 and may therefore serve as anoise cancellation microphone for microphone 230.

Noise cancellation operations may be performed using analog circuitry orusing digital processing techniques. Digital audio processing operationsfor implementing noise cancellation and for implementing other functionscan be performed locally in accessory 14 or can be performed remotely indevice 12. As shown in FIG. 4, circuitry 192 may include audioprocessing circuitry 232. Circuitry 232 may include analog-to-digitalconverter circuitry 234 (e.g., for digitizing analog audio signals fromthe microphone in accessory 14) and digital-to-analog convertercircuitry 236 (e.g., to convert digital signals to analog signals thatare played back through the speakers of accessory 14).

As described in connection with FIG. 2, accessory 14 may communicatewith device 12 over path 16. Path 16 may include wires that areconnected to respective electrical contacts in connector 34 and therebyelectrical interface 238. Path 16 may also include an optical path(shown as path 200) that is connected to optical interface 252.Electrical interface 238 may include switching circuitry (e.g.,switching circuitry 164 of FIG. 2) and electrical transceiver circuitry241 such as transmitter 240 and receiver 242. Transmitter 240 andreceiver 242 may be used to support electrical communications withcorresponding receiver and transmitter circuits in electricaltransceiver 190 (FIG. 3). Switching circuitry 164 (FIG. 2) may be usedto adjust the electrical paths in accessory 14 to support a desired modeof operation. In particular, circuitry 164 of FIG. 2 may be used toconnect microphone contact M, left and right channel contacts L and R,and ground contact G to appropriate circuits in accessory 14 whileswitching circuitry 160 in device 12 is used to connect thecorresponding contacts in connector 38 to appropriate circuits in device12.

Optical communications over path 16 may be supported using opticaltransceiver 202 of optical communications interface circuitry 252.Transmitter 244 may contain an optical source such as source 246. Source246 may contain one or more laser diodes, light-emitting diodes, etc.Receiver 248 may include a detector such as detector circuitry 250.Detector 250 may include one or more photodetectors for receiving lightsignals that have been transmitted over optical path 200 from device 12.

Circuitry 192 may use electrical interface 238 to support electricalcommunications with device 12 over path 16. Circuitry 192 may useoptical interface 252 to support optical communications with device 12over path 16.

Circuitry 232 may be used to locally implement noise cancellationfunctions. In a typical local noise cancellation arrangement usingdigital processing techniques, analog microphone signals are digitizedusing analog-to-digital circuitry 234. Processing circuitry 232 receivesaudio signals (e.g., played back music) from device 12 over path 16 indigital form (optical or electrical). Audio processing circuitry 232 maythen use digital processing techniques to cancel noise from the playedback audio. The resulting audio signal may be converted to analog forspeakers 224 and 228 using digital-to-analog converter circuitry 236.

In a typical remote noise cancellation technique, circuitry,analog-to-digital converter circuitry 234 may be used to digitizeambient noise signals from noise cancellation microphones in accessory14 such as microphone 222, microphone 226, and microphone 231.Electrical interface 238 and/or optical interface 252 may be used totransmit these signals to accessory 14. An advantage of using opticalpath 200 to convey digital audio signals from accessory 14 to device 12is that optical path 200 is generally not subject to electricalinterference and may be able to support signals with relatively largedata rates. Device 12 may receive the digital noise cancellation signalsfrom the noise cancellation microphone using transceiver 190 and/ortransceiver 210 (FIG. 3). Audio digital signal processor 188 may then beused to perform noise cancellation operations. The resultingnoise-cancelled audio signal can be returned to accessory 14 over path14 (e.g., using analog output from codec 182, electrical digital signalsfrom transceiver 190, or optical digital signals from transceiver 210).In accessory 14, analog signals may be routed to speakers 224 and 228.If the noise-cancelled audio is provided in digital form, electricalinterface 238 and/or optical interface 252 can provide these signals tocircuitry 232. Digital-to-analog converter circuitry 236 may thenconvert the digital audio to analog audio to play back on speakers 224and 228.

If desired, other features may be implemented locally and/or remotely.For example, accessory 14 may use circuitry 192 to locally process userinput data such as button actuation data, video, images, or sensor data.These signals may also be processed remotely by conveying local signalsto device 12 over path 16 using electrical interface 238 and/or opticalinterface 252. The use of audio processing circuitry 232 to implementlocal and remote processing operations is merely illustrative.

If desired, device 12 may be coupled to external equipment that servesas an interface between multiple devices. This type of arrangement isshown in FIG. 5.

As shown in FIG. 5, system 10 includes electronic device 12. Electronicdevice 12 includes electrical interface circuitry (transceiver) 190 andoptical interface circuitry (transceiver) 210. Path 16A may includeelectrical path 88A and optical path 200A. Path 16A may be used toconnect electronic device 12 to electronic equipment 14A. Equipment 14Amay use electrical interface circuitry 238A (electrical transceivercircuitry) to communicate with device 12 over electrical path 88A.Equipment 14A may use optical interface circuitry 252A (opticaltransceiver circuitry) to communicate with device 12 over optical path200A.

Equipment 14A may serve as an interface (sometimes referred to as abreakout box) between device 12 and one or more additional pieces ofequipment 14B. The devices that are interconnected in system 10 of FIG.5 can be, for example, consumer electronics devices such as receivers,set-top boxes, and televisions. The interconnected devices may alsoinclude computers, audio equipment (e.g., musical instruments, studiomonitors, sound effects boxes, etc.), video equipment (e.g., displays,video processors, etc.), printers and other peripherals, communicationsequipment, etc.

As shown in FIG. 5, equipment 14A may use electrical interface circuitry238A to communicate with corresponding electrical interface circuitry238B (transceiver circuitry) in one or more pieces of equipment 14Busing electrical paths 88B in paths 16B. This allows power and/orelectrical data signals to be distributed to equipment 14B usingequipment 14A. The power and/or data signals may originate in device 12or may originate in equipment 14B. Equipment 14A may also use opticalinterface circuitry 252A to communicate with corresponding opticalinterface circuitry 252B (transceiver circuitry) in one or more piecesof equipment 14B using optical paths 200B in paths 16B. This allowsoptical signals from device 12 or one of devices 14B to be distributedto other equipment in system 10.

Consider, as an example, the use of equipment 14B as an audio breakoutbox. In this type of arrangement, equipment (device) 12 may be acomputer with one or more audio and video cards. These cards may becoupled to equipment 14A using path 16A. Equipment 14B may includemusical instrument equipment such as guitars, synthesizers, studiomonitors, voice microphone, instrument microphones, etc. In equipment14B, optical interface circuitry 252B may be used to carry digitaloptical data such as digital audio data. For example, in a synthesizer,the optical path between the synthesizer and breakout box 14A may beused to carry musical instrument digital interface (MIDI) data and/ordigital audio. In a guitar, the optical path between the guitar andbreakout box 14A may be used to carry digital audio data from pickups oron-board effects circuitry in the guitar. Microphones and studiomonitors may use the optical paths to carry digital audio data.

To support legacy cables and to enhance compatibility with equipmentthat does not necessarily contain optical paths, the hybridoptical-electrical connectors that are used in system 10 may use avariety of form factors. For example, the connectors on one or both endsof the cables in paths 16A and 16B may be USB connectors, audioconnectors such as 3.5 mm jacks and plugs or quarter-inch jacks andplugs, male and female XLR connectors, other connectors, or combinationsof these connectors. A cable may have, as an example, a hybridelectrical-optical connector on one end and a larger or smaller audioconnector or other connector on the other end. The hybrid connector inthis type of arrangement may be based on a USB form factor, an XLR formfactor, an audio connector form factor (e.g., 3.5 mm or quarter inch,etc.), a connector that is based on an XLR-¼″ audio connector hybrid,etc. The connector on the other end may have conventional electricalcapabilities and may be based on a USB form factor, an XLR form factor,an audio connector form factor (e.g., 3.5 mm or quarter inch, etc.), aconnector that is based on an XLR-¼″ audio connector hybrid, etc.Circuitry in the cable or elsewhere in the system may be used to convertbetween optical and electrical signaling formats. The electrical pathsin the cables may be balanced or unbalanced. Each piece of equipment insystem 10 may have mating connectors that receive the connectors at theends of the cables.

As shown in FIG. 6, path 16 may be provided with hybridoptical-electrical connectors at both ends. Device 12 may have aconnector such as connector 254 that contains both electrical (“E”) andoptical (“O”) interfaces (transceivers). Cable 70 may have a pair ofoptical-electrical connectors. Optical-electrical connector 256 may havean optical path and electrical contacts that mate with a correspondingoptical path and electrical contacts in connector 254 of device 12.Optical-electrical connector 258 may mate with optical-electricalconnector 260 in device 14. Devices 12 and 14 may be cellular telephonesor other electrical devices, accessories such as headphones or otherelectrical equipment, etc. Device 14 may have optional additionalconnectors such as optical-electrical connector 262 for interfacing withadditional components (e.g., as described in connection with FIG. 5).Device 12 may also have more than one optical-electrical connector ifdesired.

An arrangement of the type shown in FIG. 6 may be satisfactory when itis desired to interconnect pieces of equipment that each contain aconnector for receiving a mating cable connector. In some situations, itmay be desirable to use a hardwired cable connection in place of or incombination with a connector-type arrangement. For example, a headsetmay have a cable pigtail that has a connector. In this situation, thecable in path 16 may have one end that has a connector and one end thatis connected directly to circuitry in a device without using aconnector. A configuration of this type is shown in FIG. 7. As shown inFIG. 7, device 12 may have an optical-electrical connector 254. Cable 70in path 16 may have a connector at one end such as connector 256.Connector 256 may mate with connector 254 to support optical andelectrical communications. In device 14, the wires and optical path incable 70 may be hardwired to electrical and optical interface circuitrywithout using a connector (shown as hardwired connection 264 in FIG. 7).Device 14 in FIG. 7 may have connectors such as optical-electricalconnector 262 to interface with additional equipment (e.g., as describedin connection with FIG. 5).

Cable 70 may contain optical-electrical interface circuitry. Anarrangement of this type is shown in FIG. 8. As shown in the FIG. 8example, cable 70 may contain interface circuitry 266. At one end, cable70 may have an optical-electrical connector (connector 256) that mateswith optical-electrical connector 254 of device 12. Optical-electricalconnector 256 may have an optical path formed from a fiber and/or otheroptical coupling structure and electrical contacts. The optical path andelectrical contacts of connector 256 may mate with a correspondingoptical path and electrical contacts in connector 254 of device 12. Atits other end, cable 70 may have an electrical connector (connector 268)having electrical contacts that mate with electrical contacts incorresponding electrical connector 270 of device 14. An electrical pathmay be formed directly between the electrical contacts of connector 256and connector 268 and/or wires in the electrical path that originate atthe electrical contacts of connector 256 may terminate at electricalterminals associated with interface circuitry 266. When electricalsignals from connector 256 are received by interface circuitry 266,interface circuitry 266 may retransmit these electrical signals on someor all of the electrical contacts in connector 268 and vice versa.

Device 14 of FIG. 8 may have other ports (e.g., ports formed byelectrical connectors 276) to support connections with additionalequipment. Interface circuitry 266 may contain optical-to-electricalconverter circuitry 272 and electrical-to-optical converter circuitry274. Circuits 272 and 274 may include optical transceiver circuitry tosend and receive optical signals and electrical transceiver circuitry tosend and receive electrical signals. For example, optical-to-electricalconverter circuitry 272 may include a photodetector.Electrical-to-optical converter circuitry 274 may include a lightsource. During operation, device 14 may use a light source to transmitoptical signals through the optical path in connectors 254, 256, andcable 70. Circuitry 272 may receive the optical signals from the opticalpath in cable 70 that have been transmitted by device 12 and, using thephotodetector, may produce corresponding electrical signals that aresupplied to device 14 using electrical connector 268 and matingelectrical connector 270. Circuitry 266 may receive electrical signalsfrom device 14 via connector 270 and connector 268 and may use the lightsource of electrical-to-optical circuitry 274 to produce correspondingoptical signals. These optical signals may be conveyed to device 12using the optical path in cable 70.

In arrangements of the type shown in FIGS. 6, 7, and 8, theelectrical-optical connectors and electrical connectors may beimplemented as 3.5 mm TRS audio connectors or other audio connectors,may be implemented as XLR connectors, or may use other suitable formfactors. The optical paths in cable 70 may be formed form a singleoptical fiber that is coupled to wavelength-division-multiplexingfilters and corresponding sources and detectors. For example, a singlefiber may be used in the arrangement of FIG. 8 to convey optical signalsfrom connector 256 to optical-electrical interface circuitry 272. Ininterface 266, a wavelength-division-multiplexing filter may be used toroute light from the optical path of cable 70 that has a firstwavelength to the photodetector in circuitry 272 and may be used toroute light that has a second wavelength from the light source incircuitry 274 to the optical path of cable 70.

A cross-sectional side view of an illustrative cable such as cable 70 isshown in FIG. 9. In the example of FIG. 9, cable 70 has four wires 278and a single optical fiber (fiber 280). Wires 278 and fiber 280 may beencased in jacket 282. Additional components may be included in cable 70if desired (e.g., strands of strengthening fiber, dielectric filler,metal braids or foils (e.g., for electromagnetic shielding), etc. Wires278 may be formed from a solid conductor (e.g., solid copper wire) orfrom stranded wire. A plastic coating or other insulator may surroundeach wire to prevent short circuits. Fiber 280 may be formed from amaterial that is transparent to light (e.g., to infrared or visiblelight). Suitable materials for fiber 280 include plastic and glass.Fiber 280 may be a multimode fiber or may be a single mode fiber. One ormore layers (e.g., a core layer, a cladding layer, strengthening layers,etc.) may be included in fiber 280.

Wires 278 may be used in forming an electrical path in path 16. Fiber280 may be used in forming an optical path. Although four wires and asingle optical fiber are shown in the illustrative cross-sectional viewof FIG. 9, this is merely an example. Cable 70 may contain fewer thanfour wires or more than four wires and may contain one, two, or morethan two optical fibers. For example, cable 70 may contain two opticalfibers 280, as shown in FIG. 10.

When path 16 contains a single optical fiber, optical signals may besent in one direction. For example, a transmitter in device 12 maytransmit optical signals to a corresponding receiver in equipment 14 ora transmitter in equipment 14 may transmit optical signals to acorresponding receiver in device 12. Bidirectional communications mayalso be supported. With one suitable arrangement, a time divisionmultiplexing scheme may be used to support bidirectional communications.In a time division multiplexing scheme, device 12 and equipment 14 maytake turns in using the optical path. During certain time periods,device 12 can transmit optical signals to equipment 14. During othertime periods, equipment 14 can transmit optical signals to equipment 12.

Simultaneous bidirectional communications over a single fiber may alsobe supported. For example, multiple wavelengths of light may be used inthe system. Electronic device 12 may transmit upstream data using lightat a first wavelength while equipment 14 is simultaneously transmittingdownstream data using light at a second wavelength. When cables containmultiple fibers (as with the illustrative cable of FIG. 10), one fibermay be used for upstream communications while the other fiber is beingused for downstream communications. Each fiber in a multi-fiber cablemay also be used for bidirectional communications using time-division orwavelength-division multiplexing techniques.

In cable 70, the optical fiber that makes up the optical path may belocated in the center of the cable (i.e., running along its longitudinalaxis in a coaxial fashion) or may be located in other suitable portionsof the cable (e.g., near the plastic jacket or intertwined with otherstrands of material). In the optical-electrical connectors, the opticalfiber can be coupled to transparent structures that help guide light toand from the optical fiber. These transparent structures may includecoaxial lengths of fiber, annular (ring-shaped) transparent insulators(e.g., insulators that serve both as transparent conduits for light andas electrical insulators that isolate electrical contacts in theconnectors from each other), etc.

An illustrative configuration that may be used for an optical-electricalaudio plug and a mating optical-electrical audio jack is shown in FIG.11. As shown in FIG. 11, audio connector 38 (e.g., a TRS audio jack) maycontain electrical contacts 74, 76, 78, and 80 (labeled T, R1, R2, andS, respectively) and may have an associated optical transceiver 208. Thediagram of FIG. 11 shows plug 34 partially inserted into jack 38. Whenplug 34 is fully plugged into jack 38, electrical contacts 48, 50, 52,and 54 (labeled T, R1, R2, and S, respectively) form respectiveelectrical connections with mating contacts 74, 76, 78, and 80. Opticalpath 200 may be placed in contact with transceiver 208 or may be placedsufficiently close to transceiver 208 that optical signals (light) maybe coupled between transceiver 208 and path 200. If desired, jack 38 mayinclude an optical member such as member 206 of FIG. 2 that isinterposed in optical path 200 to help convey optical signals betweeninput-output port 286 of transceiver 208 and tip 284 of optical path200. In this type of configuration, the optical member (which may be,for example, a short length of optical fiber) may serve as an extendingportion of path 200.

In configurations of the type shown in FIG. 11, there may be only asingle optical fiber in cable 70 and in connector 34. It may thereforebe desirable to use wavelength-division multiplexing techniques tosupport bidirectional communications over the optical fiber. Wavelengthdivision multiplexing may be implemented using wavelength divisionmultiplexing (WDM) optical filters. As shown in FIG. 12, for example, arespective WDM filter may be coupled to each end of path 16. In device12, source 212 may be coupled to an input port of WDM filter 288 byoptical path 290 (e.g., an optical fiber). Detector 218 may be coupledto an output port of WDM filter 288 by optical path 292 (e.g., anoptical fiber). Path 200 (e.g., an optical fiber) may be coupled to aninput-output port of WDM filter 288 (either by direct connection or viaan optical path extension such as optical path extension 206 of FIG. 2).In device 14, WDM filter 294 may have an input-output port that iscoupled to path 200, an output port that is coupled to detector 250(e.g., by optical path 296), and an input port that is coupled to source246 (e.g., by optical path 298).

WDM filters 294 and 288 combine and separate light by wavelength. Forexample, outgoing light from source 212 at a first wavelength may berouted to path 200 by WDM filter 288. In device 14, WDM filter 294 mayroute light at this first wavelength to the input of detector 250.Source 246 in device 14 may transmit light at a second wavelength thatis different than the first wavelength. WDM filter 294 may route thissecond wavelength of light onto path 200. In device 12, WDM filter 288may route light at the second wavelength to the input of detector 218.WDM filters 288 and 294 may be implemented using gratings, coupledwaveguides, etc. If more than two wavelengths are desired in awavelength division multiplexing scheme, additional WDM filters orfilters with additional ports may be used to accommodate additionalsources and detectors. WDM filter configurations of the type shown inFIG. 12 may, if desired, be used in systems of the type described inconnection with FIGS. 6, 7, and 8 (as an example).

In arrangements of the type shown in FIG. 11, optical path 200 may beformed using a coaxial fiber (i.e., a fiber that runs along the centrallongitudinal axis of cable 70 and connectors 34 and 38). Audioconnectors 34 and 38 in this type of arrangement need not be placed in aparticular rotational orientation to ensure adequate optical couplingbetween path 200 and transceiver 208, because connectors 34 and 38 inthe FIG. 11 arrangement are radially symmetric.

If desired, however, connectors 34 and 38 may be provided with alignmentfeatures that help these connectors maintain a particular desiredrotational orientation when mated. This type of arrangement is shown inFIG. 13. As shown in FIG. 13, plug 34 and jack 38 may be aligned alonglongitudinal axis 304. Plug 34 may have one or more engagement featuressuch as engagement feature 300 (e.g., a protrusion). Jack 38 may haveone or more mating engagement features such as engagement feature 302(e.g., an indentation or other recess). When a user desires to insertplug 34 into jack 38 along axis 304, the user may rotate plug 34 aboutaxis 304 in direction 306. Once the engagement features are properlyaligned (i.e., once features 300 and 302 are in rotational alignment),plug 34 may be completely inserted into jack 38.

When rotational alignment features of the type show in FIG. 13 are usedin the audio connectors, a desired rotational alignment between plug 34and jack 38 may be ensured. As a result, source 212 and detector 218 maybe located at particular known positions in device 12, as shown in FIG.14. In the FIG. 14 example, path 200 includes first fiber 280A and asecond fiber 280B. In device 14, fiber 280A is coupled to detector 250and fiber 280B is coupled to source 246. When plug 34 is connected tojack 38, alignment features 300 and 302 (FIG. 13) engage and therebyensure that fiber 280A will be properly aligned with source 212 and thatfiber 280B will be properly aligned with detector 218 (or, inconfigurations that use WDM filters, that the single fiber in path 200is aligned with the input-output port of the WDM filter).

In systems that do not use alignment features, it may be desirable toprovide plug 34 and jack 38 with radially-symmetric optical couplingstructures. Consider, as an example, the plug configuration of FIG. 15.As shown in FIG. 15, plug 34 may be provided with annular opticalstructure 310 and concentric annular optical structure 308. Structures310 and 308 may be ring-shaped transparent members that are opticallycoupled to respective optical fibers in cable 70 and that surround theprong (elongated prong-shaped member 309) on which the tip contact, ringcontacts, and sleeve contact of the plug are formed. Structures 310 and308 may be formed from clear plastic, glass, or other suitabletransparent substances (e.g., for infrared or visible light). Theexample of FIG. 15 includes two annular optical coupling structures, butarrangements with only a single optical coupling structure may be usedif desired (e.g., when a WDM arrangement of the type described inconnection with FIG. 12 is used).

Because optical coupling structures such as optical coupling structures310 and 308 are radially symmetric, use of arrangements of the typeshown in FIG. 15 help ensure that there is adequate optical couplingbetween the audio connectors (e.g., optical coupling between opticalpath 200 and transceiver 208) regardless of the rotational orientationbetween plug 34 and jack 38. If desired, one or more annular opticalcoupling structures may be included in jack 38, as shown in FIG. 16. Inthis type of arrangement, coupling structure 308 has a diameter that isgreater than the diameter of the circular opening of the cylindricalcavity that forms the interior portion of jack 38 and coupling structure310 has a diameter greater than that of coupling structure 308. Couplingstructure 308 may be used to route incoming light from optical couplingstructure 308 of plug 34 to a detector in device 14. Coupling structure310 of jack 38 may be used to route transmitted light from the source indevice 12 to optical coupling structure 310 in plug 34 (FIG. 15). Thering-shaped optical coupling structures in jack 38 and plug 34 may beused to mate with each other or may be used to mate with sources,detectors, or optical fibers that have fixed positions within theirconnectors, but that do not completely surround the connector. Forexample, annular optical coupling structures in plug 34 may be coupledwith a source and detector of the type shown in FIG. 14 or annularoptical coupling structures in jack 38 may be coupled with opticalfibers such as optical fibers 280A and 280B in plug 34.

A cross-sectional side view of a plug and jack where the ring-shapedoptical coupling structures of plug 34 are used to mate with a sourceand detector in jack 38 is shown in FIG. 17. As shown in FIG. 17, outerannular optical coupling structure 308 may be coupled to optical fiber280A and inner annular optical coupling structure 310 may be coupled tooptical fiber 280B. Annular optical coupling structure 308 willoptically couple fiber 280A to source 212, regardless of the rotationalorientation of plug 34 within jack 38. Similarly, optical couplingstructure 310 will optically couple fiber 280B to detector 218,regardless of the rotational orientation between plug 34 and jack 38.

If desired, light can be transmitted through transparent opticalcoupling structures that are formed between the electrical contacts inplug 34 and jack 38. Each of the electrical contacts in plug 34 and jack38 (i.e., the tip, ring, and sleeve contacts) may be electricallyinsulated from adjacent electrical contacts using ring-shapedtransparent dielectric structures (e.g., glass, plastic, or otherdielectric materials that are transparent in the infrared or visibleportions of the spectrum and that are electrically insulating). Thesestructures can therefore serve dual purposes. Electrically, thedielectric structures are insulators that block the flow of currentbetween adjacent electrical connectors. This prevents the electricalcontacts from becoming shorted to each other. Optically, at least someof the dielectric structures are transparent to the optical signals onpath 200. This allows the optical signals to be coupled between theoptical transceiver and optical path 200.

A connector arrangement in which transparent dielectric structures areformed between respective electrical contacts in plug 34 and jack 38 isshown in FIG. 18. As shown in FIG. 18, plug 34 may have contacts 48, 50,52, and 54 that mate with respective contacts 74, 76, 78, and 80 in jack38. Contacts 48, 50, 52, and 54 of FIG. 18 are ring shaped. Matingcontacts 74, 76, 78, and 80 may be formed using hollow rings, springmetal tabs that protrude inwards and make electrical contact with thecontacts of plug 34, or other suitable electrical contacts. In a typicalconfiguration, the contacts of plug 34 are separated by dielectric (see,e.g., dielectric band 56, which isolates tip contact 48 from ringcontact 50).

At least some of the dielectric that isolates the electrical contacts inplug 34 may also serve as transparent windows for optical signals. Inthe FIG. 18 example, ring-shaped optical band 312 may be formed from adielectric such as transparent plastic or transparent glass. Opticalcoupling structure 314 (e.g., one or more transparent plastic or glassmembers) may be used to optically couple optical band structure 312 tooptical path 280B. Optical structures 312 and 314 are interposed betweencontacts 50 and 52 and therefore may help to isolate contacts 50 and 52from each other. Ring-shaped optical band 316 may also be formed from adielectric such as transparent plastic or transparent glass. Opticalcoupling structure 318 (e.g., one or more transparent plastic or glassmembers) may be used to optically couple optical band structure 316 tooptical path 280A. When plug 34 is inserted into jack 38 as shown inFIG. 18, structures 312 and 314 may optically couple source 212 to path280B and structures 316 and 318 may optically couple detector 218 topath 280A.

With an arrangement of this type, path 280B may be used by jack 38 totransmit optical signals from device 12 and path 280A may be used byjack 38 to receive optical signals for device 12. Other arrangements maybe used if desired. For example, jack 38 and plug 34 may be providedwith a single optical path rather than multiple optical paths. In thistype of arrangement, bidirectional communications may be supported usingwavelength-division-multiplexing techniques as described in connectionwith FIG. 12 or time-division multiplexing techniques. Moreover, anyrespective pair of the contacts may be separated by a transparentinsulator structure. The separation of the R1 and R2 contacts by onesuch structure and the separation of the R2 and S contacts by anothersuch structure in the example of FIG. 18 are merely illustrative. Ifdesired, the transparent insulator structures may be formed as unitarypieces of material. The use of two or more separate pieces of adjacenttransparent material (e.g., the two-piece structures such as structure312/314 and structure 316/318 of FIG. 18) is shown as an example.

As shown in FIG. 18, jack 18 may also have transparent insulatingstructures such as structure 320 and 322 in the gaps between adjacentcontacts. These structures may, if desired, help isolate the electricalcontacts in jack 38 from each other. Structure 320 may have a fibershape, a ring shape, or other suitable shape and may be used to guidelight from source 212 into structure 312. Structure 322 may have a fibershape, a ring shape, or other suitable shape and may be used to guidelight from structure 316 into detector 218. Inwavelength-division-multiplexing arrangements, only one of transparentinsulator optical coupling structures 320 and 322 need be used. In thistype of situation, the optical coupling structure may be coupled to aWDM filter such as filter 288 of FIG. 12.

Source 212 and detector 218 (or, in WDM configurations, WDM filter 288)may be located at a particular rotational orientation around plug 34 (asshown in the FIG. 18 example) or may be formed at one or more radiallocations around plug 34. In configurations in which only one radiallocation is used (e.g., the 12:00 position of source 212 and detector218 that is shown in the FIG. 18 example), structures 320 and 322 may beused to help concentrate and guide light between that radial locationand the radially uniform ring-shaped structures in plug 34 such asstructure 312 and 316 or other transparent insulator plug structures.

If desired, engagement features such as features 302 and 300 of FIG. 13may be used in connection with connectors of the type shown in FIG. 18.When engagement features are used, the rotational orientation betweenplug 34 and jack 38 is known whenever plug 34 and jack 38 are coupledtogether. As a result, optical coupling structures 314 and 318 may beconfigured to guide light to and from a particular radial locationaround plug 34 (e.g., at the 12:00 location of the source and detectorof FIG. 18). In this way, the signal strength reductions that mightotherwise be associated with spreading out optical signals in a radiallyuniform fashion can be avoided.

FIG. 19 is a perspective view of an illustrative electronic device andan associated accessory. As shown in FIG. 19, accessory 14 may have abase 334 from which plug 34 protrudes vertically. Base 334 may serve asa stand that supports an electronic device. Base structure 334 may havea cavity 336. Cavity 336 may have a size and shape that is configured toreceive and support end 338 of device 12. Cable 330 and connector 332may be attached to additional equipment such as a computer (see, e.g.,computing equipment 20 of FIG. 1). Cable 330 and connector 332 may beused to convey analog signals, power signals, and digital data signals.When a user desires to charge a battery in device 12 or to play audioand video from device 12, the user may insert device 12 into cavity 336.In this position, cylindrical plug 34 is received in mating cylindricaljack 38. Optical and electrical paths through plug 34 and jack 38 may beused to convey data and power between accessory 14 and device 12 (e.g.,bidirectionally using time-division multiplexing and/or wavelengthdivision multiplexing techniques). If desired, the electrical contactsof the connectors can distribute power to device 12 while device 12 isconveying digital optical signals to accessory 14 using an optical paththrough the connectors. Accessory 14 can be provided with speakers orother components that allow accessory 14 to present media to the user.Accessory 14 can also use optical transceiver circuitry and/orelectrical transceiver circuitry to relay data to and from the equipmentthat is attached to cable 330 and connector 332.

FIG. 20 is a flow chart showing illustrative steps involved in conveyingelectrical and optical signals through communications paths 16 betweenelectrical equipment such as electronic device, accessories, and otherequipment. The communications paths typically include both electricaland optical paths.

At step 324, after a user has connected equipment together using paths16, the equipment in the system can perform discovery operations. Theseoperations allow the components in the system to determine what otherequipment is included in the system and therefore allow components toadjust their settings accordingly. As an example, an electronic devicethat discovers that a legacy headset that only includes electrical wireshas been attached may configure itself to support analog audio playback,whereas an electronic device that discovers that an accessory withoptical communications capabilities has been attached may configureitself to use its optical transceiver.

One way in which the equipment in system 10 may determine thecapabilities of other equipment in the system involves the use ofswitches. For example, jack 38 may be provided with amechanically-triggered, electrically-triggered, or optically-triggeredswitch (e.g., a light sensor such as a light reflection sensor) thatchanges state whenever an engagement feature such as engagement feature300 is inserted a mating engagement feature such as engagement feature302 (FIG. 13). The present of the engagement feature on the audioconnector serves as a flag that advertizes its capabilities.

Another way in which equipment in system 10 may determine thecapabilities of other equipment involves the use of communicationsprotocols. Equipment in the system may, for example, broadcast codesthat inform other equipment of their capabilities. An electric device orother accessory such as a headset may, for example, transmit optical orelectrical information to make other equipment aware of its optical (andelectrical) capabilities. Communications protocols may be unidirectional(e.g., equipment may broadcast codes without receiving significantinformation from other equipment) or may be bidirectional. In a typicalbidirectional protocol, equipment in the system may, for example,transmit information that informs other equipment of their capabilitiesin response to received queries or may exchange capability informationas part of a more complex two-way data exchange.

During discovery operations 324, equipment in system 10 may discoverinformation on other equipment such as what type of communicationsprotocols the equipment supports, what type of transceivers theequipment contains, whether the equipment contains an opticaltransceiver, etc.

At step 326, the equipment in the system may perform link setupoperations. For example, the equipment in the system can exchangepackets of digital data that inform the other equipment of desired clockrates, desired transmission powers for optical signals, desiredcommunications formats (e.g., whether error correction capabilities willor will not be present, data rate limits, etc.), desired power supplyvoltages to be conveyed (if any), and other link settings.

As an example, consider a situation in which device 12 and equipment 14each contain a light-emitting-diode (LED) source. Due to the quality ofthe optical coupling formed when plug 34 is inserted into jack 38 andother variables, the attenuation of optical path 200 may be uncertain.During the operations of step 326, device 12 and equipment 14 may sendtest light pulses while making corresponding power measurements withtheir detectors. Based on these measurements, device 12 and equipment 14may then negotiate to establish optimal optical signal levels for use incommunicating over path 16. Negotiations may take place using theelectrical path and/or using the optical path. By negotiating optimalsignal power levels, power consumption can be minimized, therebyenhancing efficiency.

A typical optical power negotiation process may initially involvetransmission of a test packet from an accessory at an initial power P1(e.g., a low or lowest power setting). In response, the electronicdevice may use its optical transceiver to measure the amount of power inthe received optical signal. Once this power level has been measured,the electronic device can respond to the accessory. For example, theelectronic device can respond to the accessory using the electricaltransceiver in the electronic device. The response of the electronicdevice may indicate that the power P1 is an acceptable level for use infuture optical communications over the link. If the measured power islow, the response of the electronic device may request that theaccessory increase its optical transmission power. This negotiationprocess may continue until the two devices reach agreement on anacceptable optical power level to use for the link. Optical transmittersin both the electronic device and the accessory may be calibrated inthis way.

After communications links between the equipment in system 10 have beenestablished at step 326, the equipment may use these links during normalsystem operation (step 328). For example, the optical and electricalpaths in links 16 may be used to convey video data (including audiosoundtracks), audio data (e.g., for noise cancellation schemes), controlsignals, etc.

The foregoing is merely illustrative of the principles of this inventionand various modifications can be made by those skilled in the artwithout departing from the scope and spirit of the invention.

What is claimed is:
 1. An audio-video jack, comprising: a plurality ofelectrical contacts including a tip contact, at least one ring contact,and a sleeve contact; and an optical coupling member interposed betweenan adjacent pair of the electrical contacts that receives opticalsignals, wherein the electrical contacts surround a cylindrical cavitywith a circular opening that receives a substantially cylindrical plugand wherein the optical coupling member comprises a transparentinsulator that separates one of the electrical contacts in the adjacentpair of contacts from the other of the electrical contacts in theadjacent pair of contacts.
 2. The audio-video jack defined in claim 1wherein the optical coupling member comprises a ring-shaped opticalcoupling member.
 3. The audio-video jack defined in claim 1 wherein theaudio-video jack comprises an engagement feature that mates with acorresponding engagement feature on a plug that is configured to bereceived within the audio-video jack.
 4. The audio-video jack defined inclaim 3 wherein the engagement feature comprises a recess that receivesa protrusion on the plug.
 5. The audio-video jack defined in claim 1further comprising an optical detector that is optically coupled to theoptical coupling member.
 6. The audio-video jack defined in claim 1further comprising a light source that is optically coupled to theoptical coupling member.
 7. The audio-video jack defined in claim 1wherein the optical coupling member comprises one of two opticalcoupling members each of which is interposed between a respectiveadjacent pair of the electrical contacts.
 8. The audio-video jackdefined in claim 7 wherein the audio-video jack comprises an engagementfeature that mates with a corresponding engagement feature on a plugthat is configured to be received within the audio-video jack.
 9. Theaudio-video jack defined in claim 8 wherein the engagement featurecomprises a recess that receives a protrusion on the plug.
 10. Aconnector in an electronic device that is configured to receive a matingconnector having an elongated prong member with at least tip, ring, andsleeve contacts and an optical path, the connector comprising: aplurality of electrical contacts surrounding a cylindrical openingconfigured to receive the elongated prong member, wherein the electricalcontacts are separated from each other by gaps; and an optical detectorthat receives light through one of the gaps.
 11. The connector definedin claim 10 further comprising a transparent insulator located in thegap through which the light is received by the optical detector.
 12. Theconnector defined in claim 10 further comprising: a light source that isconfigured to transmit light through an additional one of the gaps. 13.The connector defined in claim 12 further comprising a transparentinsulator located in the gap through which the light is received by theoptical detector.
 14. The connector defined in claim 13 furthercomprising an additional transparent insulator located in the additionalone of the gaps.
 15. The connector defined in claim 14 wherein thetransparent insulator and the additional transparent insulator compriseclear plastic.
 16. The connector defined in claim 14 wherein thetransparent insulator and the additional transparent insulator comprisering-shaped transparent insulator structures that surround thecylindrical opening.